Automatic or semi-automatic telephone system.



A. B. SMITH AUTOMATIC 0R semmummmc TELEPHONE SYSTEM. un/mo" FILED mmzs.I914.

1 ,267, 1 31 atented May 21,1918.

5 SHEETS-SHEET l.

Q Q m Y? m mg WT/YEISSES Z VVE/VTOR- M a) W A. B. SMHH.

AUTOMATIC OR SEMI-AUTOMATIC TELEPHONE SYSTEM.

lW/Tzvbs a 4M w- 12% 1 1f um/c MM;

AP LICATION FfLEU MAFLZS I914 :[EEMW Patented May 21, 1918.

5 SHEEISSHEET 2.

A. B. SMITH. AUTOMATIC 0R SEMI-AUTOMATIC TELEPHONE SYSTEM. APPUCATIUNHLEU' MAR- 25. l9l4.

5 SHEEIS-SVHEIIIT 3.

O Q JQ 4 I/V/TNESSES MGR Az'rHuz 5. 5M1TH Patented May 21, 1918.

A. B. SMITH.

AUTOMATIC 0R SEMI-AUTOMATIC TELEPHONE SYSTEM.

APPUCATIDN HLED MAR. 2512914.

Patented May 21, 1918.

5 SHiEIS- SHEET 4.

XVI/:2 21 705".- AETHUE 5 5M! TH Ma m- AUTOMA IC 0R SEMLAUTOMAHCTELEPHONE SYSTEM.

APPLICAHON EILED MAR. 25. 19:4 1,267,131.

Patented May 21', 1918 5 SHEETS-SHEET 5.

V/T/VESSES' Mid M UNITED STATES PATENT OFFICE.

ARTHUR BESSEY SMITH, OF EVANSTON, ILLINOIS, ASSIGNOR TO AUTOMATICELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC OR SEMI-AUTOMATIC TELEPHONE SYSTEM.

Application filed March 25,

To all whom it may concern:

llo it known that I, Ann-Inn Basso!" b'ilrrn. a citizen of tho [initcdStates of America. and resident of Evanston, Cook county, Illinois. havo invcnted certain now and useful lnun'omnlcnts in Automatic or SemiAutomatic 'lclcphonc Systems, of which the following is asl'iecification.

My invention relates to in'iprovemonts in automatic or semi-automatictelephone systoms and has for its object the provision of such a systemin which phantom circuit (a employed for establishing connectionsllerelolore attempt has been made to use phantom circuits in telephone.systems, but in every instance, as; fa as I am aware, the plrvsiealcircuits on which the phantom cirrail is slum-imposed have been usedonly for establi hing manual connections, but I believe that Illlil thefirst, to employ these physical circuits for tho purpose o'lfestablishing a call through automatic switches, In order to accomplishthis it is necessary that that part of the physical circuits on whichthe phantom circuit is superimposed shouid he insulated from the rest ofthe physical circuits in order to prevcnt any interhu'encc with thephantom circuit.

A feature of my invention, therefore, rclates to this insulation of thatpart of the physical circuit which is employed by the phantom circuit.together with the provision of means whereby a call can ho inadc autolnatieallv over such a physical circuit williout interfering in any waywith tho phantom circuit. The phantom circuit can he employed either incommotion with a call which is established autonulticalljl', or with acall which is established manually, al though I have shown specificneans where-- by this phantom circuit can be employed in an automaticcall. Likewise the connection can he made to the physical circuit cithcrillitOlllfli-i f i Q or through an opcrators manual board.

These and other features and objects of my invention will. he morereadily understood by reference, to the accompanying drawings, in whichI have illustrated my invention in connection with certain specificmeans for extending a connection to and from the physical circuits andthe phantom circuit of the trunk. As illustrated. those means involyeautomatic switches of well.- known types, and as the specific form ofSpecification of Letters Patent.

Patented May 21, 1918.

1914. Srial No. 827,063.

theso switches which are employed for extending the connection to andfrom this trunk line forms no part of my present in vention. and asthese switches are fully doscribcd in the publications and patents heroinaftcr referred to, a detailed description of these various switcheswill not be given, except in so far as is necessary for a clearunderstanding of the various features of my invention.

In the drawings, Figures 1 to 7, inclusive, are diagranunaticrepresentations of a cireuit (Ulllltfitlnll established between a calling: subscriber in Fig. 1 of one exchange and a called sul'iscriher inFig. 7 at another oxchange in a system embodying the features of l\]invent'iml. Fig. 8 shows the mechanical details; and construction of apolarized relay with modifications which may be used in connection withmy system at 49, 73. etc. for repeatingimpulses ov er the physical eii.euit.

Figs. 1 and 2 taken together represent; up paratus at the first saidexchange. There is herein shown a subscribcrs substation A, the linoconductors of which terminate in an individual or line switch C. Theline sw-iteh shown at (l is one of a group of similar lino switches, theplungers (not shown} of which engage a shaft and are controlled by theoperation ofthe master switch D in sueh a manner that they are, when innormal position, held directly in front of the terminals of a trunk lineleading to a seleclor F. Certain levels of the said selector hankscontain trunk lines which lead through a group of relays M over thetrunk lines to the internu-diate exehangc. It i:= of course. understoodthat'certain other levels of said selector banks may lead to variousother apparatus in said exchange for cou1 pletingz connections withinsaid exchange.

l igsQZl. 4 and 5 taken together represent apparatus at the intermediatcor second exchange. It will, of course, he understood that thesubscribers substations of this taxehangrc may he of any type"whatsoevt-rr and that the said exchange contains the necessaryapparatus (not shown) for completing; connections within the exchange.The relays N form'the connecting link between the trunk lilies leadingfrom the first said exchange to the selector F in the second ex change.(crtain levels of the said selector,

hanks terminate in groups of relays K,

i Ct,

which in turn connect with answering jacks the said jacks being locatedin a manual board in said exchange. The said manual board contains,together with other apparatus, the cord circuits (Y). which cordcircuits are adapted for extending connection from jacks j tojacks Thesaid jacks are the terminals of the conductors leading to a group ofrelays Q (Fig. 5), which relays are connected to trunk lines leading toa.

third exchange. shown in Figs. 6 and 7. The 7 function of the repeatersI (Fig. will be hereinafter explained.

Figs. 6 and 7 taken together represent apparatus in the third-mentionedexchange. It is. of course, understood that the subscribers substatitmsof said exchange, as in the above case. may be of any type whatsoeverand that the said exchange contains the necessary apparatus (not shown)for con pleting connection within the exchange. The group of relays J(Fig. l) form the connecting; link l'ietween the trunk lines leadingfrom the said second exchange to the connector H in the'lbird exchange.The said connector switches complete the connection to the calledsubstation through the medium of the line switch Figs. 2 and 3 takentogether represent three trunk lines connecting the first said exchangewith the second exchange. two of the said trunk lines being what areknown as physical circuit trunk lines. while the third trunk line isknown as a phantom circuit trunk line.

Figs. 5 and 6 taken together represent three trunk lines connecting theaforesaid second exchange with the. third exchange. Two of the saidtrunk lines. like in the above-mentioned case, are what are known asphysical circuit trunk lines. while the third trunk line is what isknown as a phantom circuit trunk line.

While in these drawings I have indicated the trunk lines terminating inone certain type of automatic switch. it will. of course. be understoodthat in ordinary practice. suitable Selector switches may be insertedthroughout the system without departing from the l'n'inciples oi myinvention. For example: Referring to Fig. 7. instead of connecting thetrunk linc Sit--81 directly to the connector switch H. a suitableselector or a. plurality of selector switches. similar to the selectorE. may 'be inserted between the trunk line 8(l-8l and the connectorswitch H.

'lhere isshown throughout the drawings a plurality of batteries. namelyB. B and B", each having one terminal grounded at (l. Each excha go isshown provided with one of said bstttries .for supplying current foroperating the central otiiee equipment and for furnishing talkingcurrent. There is likewise shown a plurality of batteries B,

B and I. These are preferably double voltage batteries. in, theirvoltage is higher than the voltage. of the be'forc-inenlioned batteries.The use of these batteries will hereinafter be explained.

The automatic substations A and A may he of any suitable or ap n-ovcdtype. lieferring to the substation A. as herein shown it comprises theusual receiyer l, transmitter 3, SWltt'LJUOli 4., ringer 5 and condenser(7. Being an automatic substation. it is also PI'OVldcd with an impulsetransmitter or calling device which is re )rcsented herein by a pair ofimpulse springs 7 and 8 and an impulse. wheel J, which latter is assumedto be controlled through the medium oi a finger hole dial (N t shown) insuch a main ner that the imprise springs 7 and H may be momentarilyseparated a number of times corresponding to the digit called.

The sulnscriber's individual sw itch is of the general type ofsubscribefs switch shown in. liritish patent. to R. \V. James No. 26.301of 1906, being, however. of the particular type disclosed in Britishpatent to '1. (1. Martin No. 1419 of 1910. This line switch comprises.among other details. a plunger (not shonn) attached to the end of the socalled plunger arin l (l. which is controlled by the magnet 11. lhemagnet 11 comprises four windings. namely. a pull-down winding 12, acut-oil or holding winding 12 a line winding 14. and an auxiliary orholding winding 15. The core of the magnet 10 is so constructed that themagnetic circuit o!' the windings 12 and 13 is sepaate from that of thewindings 1i and 1:"). The winding 12 operates both the plunger arm 10and the armature 16, while the winding 13 is only strong enough tooperate the cnhotl' armature 1,6 and to hold the plunger arm 10 in itsoperated position. When the plunger arm 10 is operated, the plunger isforced into a bank of contact springs, forcing the Springs 1. 18. 19 and20 into engagement with the springs 21, 22. 23 and 24. respectively.Although only one set of springs (1724.) is shown. each line switch isprovided. with a plurality of such sets. each set, forming the terminalof a trunk line leading to the selector E. llach trunk line is connectedin multiple with the corresponding springs of all the line. switches oithe group which is-controlledby the master switch l). The switch (l iscontrolled by the subscriber through the medium of the line relay M, aswill be hereinafter more fully explained.

The master switch I) is of the general type disclosed in British PatentNo. 26.301 of 1906. hercinabove referred to. being. however, of theparticular type disclosed in said British Patent No. 1419 of 1910. Thetunc tion of the master switch. as is well known. is to maintain theplungcrs of all the idle line witches in pmition to engage the terminalsof an idle trunk line.

The aeleetor switch F. is of the general type ol selector switch(list'losed in linited t tzttes l miter latent Xo. M55321, granted Ma eh-l. ltllhi to Keith. lirh'rhmn and lilllltr-lfllh except that theso-called Hide eu'itrh ii omitted and the eireuite are modi tied toadapt the mitt-h to operate in a system in whirl] it s eontrolled himpulse: delivered over two sides of the line in writ-s in the mannersheu'n in British Pat ent Xo. W517? of .1913. granted to T. (l, Martin.Among other details. the selector ll comprises a hank of contactsarranged in horizontal rows or level whi 'h eontacts are adapted to heengaged h a set of wipers it; and 27 carried upon a Shaft (not vshown)which has a vertical movement controlled lJ the vertical magnet and arotary movement controlled by the rotary magnet 21 The operations of\ariote: parts of the wilt-h are etmtrolled through the. medium oi. adouhle-Wound line relay l". .lleann for permitting" the 4\\'llfjli to herei-tored to normal po ition are provided in the release magnet ill,which. upon each giving. it ithdrawa lite retainin; pupils from thehatt. The springs 32 and 11 3 close out when the szuitrh shaft ha: beenraised one or more steps from its lowest position. The relays 34- and 35are slow acting: relaythat is, the de'energize slowly after their en:rg'izing circuits are broken.

Jhe group of relays M (Fig. 2) ('onneet "the hank terminals 36, 37 and35% of the.

selector E with the trunk line 39--40. The battery B is bridged acrossthe conductors 41-43 through the windings ot the slow acting; polarizedrelay t-7'in series with the windings 44 and 4.5 of the repeating coilS. The impulses of current, transmitted through the windings 44 and l-5of the re pcating; coil due to the momentary separation of the impulsesprings 7 and d of the substation. 1L operate to induee iinpulnes ofcurrent in the windings 4 7* and 45 of the said repeating coil S. Thesaid induced im pulses extend from the point 69 through the Winding 46of the repeating eoil S, over the trunk conductor 40, windings 51 and 50of the repeating coil S in series with the polarized relay 49, over thereturn condue tor 39 and through the Winding 47 of the. repeating coil Sback to the starting" point. The polarized relay 49 is constructed withtivo'separate armaturefi, namely, 54- and 55. It is well known that animpulse of current igenerated-in the secondary of an inducton coil whena circuit is established in he primary as well as when thocircutl,hroken, l'loweyer, it is alklo tvell known tilmf the circuit through theprnnary of the safe coil may he o arranged with regard to resi tanceand. voltage that this impulse which the circuit is broken.

in induced in the secondary when the primary circuit is estahlished lHeither st rongrcr or weaker than that whieh is indueed when Therefore.in my syn-- tom in Whieh the impulse on the hrealr alone is utilized theprimal"; circuit in so arranged that the impulse induced when thecircuit la estahlis'hed in the weaker and the arlnaturea oi thepolarized relay l9 may he easily adjusted no that this weaker impul ewill not :ill'eet them. The armature 5-l responds lo in'tpulses ofeat-rent transmitted through the relay ll in one direetiou. and thearmature 5:3 respond to the impiIl e il'ttltfill'tlll'ttl through therelay 49 in the op posite, direet ion. The mid relay -l-5l is soeonntrueted and adjueted 2H not to respond to butter;' current over thephantom circuit trunk line. lhe relays i7 and eontrol the operation ofthe switches loeat'ed in the intermediate exehang't'n 'l'he relays titand (3; control the application of halter from the high voltage hatterIt to the eondur lors -11 and ill for releasing purpooes. \\'lll('ll illhe ln-reinal'ler more l'ull explained. The operation of the uroupa olrelays M and N of the truulc line oz: t'll is similar to th operation ofthe groups ol rela \I and N of the trunl-z line I!t-lll. lhe eonduetorsGit" and t3?) and lit} and ti? are the phantom taps of th trunk linenaw- -l0 and oIr tS-i. 1 preferably join thepoinn tlS--t3tl and 7tl71 ofthe repeatin; (oils h and S thus Fhort-eireuiting the polarized relaysl8 and 72. i'esl'iectirelv. in it is well known h those versed in theart that there is not am dilierenee of potential lietneeu correspondingpoints on the two conductors forming one limb of the phantom circuit.the halanee of my phantom eircuit in not afi'eet'ed h\' eonnecting saidpoints together. and the resistance. of each of in}: physical circuitsin somewhat decreased, thus giving stronger indueed impulses to operatethe arn'tatureg of the polarized relays 49 and T -L l'thptfllll'tflk.

lhe repeater l is adapted to reeeive iiiipulses from the enlist'atlonand to repeat them over the phantom trunk line to a seeonrl exchange.i-\n'ion,Q; "therdetails, it comprises a double-wound line rela) T4 andthe slow acting" relays and Ttl The slow aet ing relay 'itl oi'ieratesto eat the eondensers :57 and 78 out of circuit While the repeater 18operating to repeat. impulses to the said seeoud exehange.

The selector F is Similar in all respects to the selector 1).

The device K eonsists ot' a p'luralitr ol relays! together with thouaual line Kl QHitl lamp 7!) and answering jack j.

The cord eireuit O is provided nith the usual supervisory signal 82 andthe tlt't'th' sary relays for controlling the same. When the key K isoperated, the slow acting relay R2 operates t tran mit an impulse ofeurrent over the conductors 84; and 85. The function of said preliminaryimpulse of current will he hereinafter explained.

The trunk lines 8(i87 and 88-89 (Figs. 5 and (i) are similar to thetrunk lines ink-t0 and (i3--(3l, except that they are arranged to beseized manually, (a, by means of a plug and jack, instead of by anautomatic switch. It will also be seen that the trunk line Sit--87 isarranged for extending a connection in one direction. while the trunkline 88--89 is arranged for extending a connection in the oppositedirection. The conductors 90 and 9t and 9; and 93 form the phantom tapsoi' the trunk lines St --87 and 89-39, as in the irevious case.

The connector H (Fig. 7) is oi the same eneral type of connectordisclosed in United States Letters Patent No. 815,176, granted March 13,1906, to Keith, Erickson and Erickson, the circuits, however, beingn'ioditied to adapt the switch to operate in a systent in which thecentral otiice apparatus is controlled by impulses delivered over thetwo sides of the line in series. Like the lectors. the connector isprovided with a shaft (not shown) carrying the wipers 9t, 95 and 90,which shaft is controlled by the vertical magnet 97 and the rotarymagnet 98. The usual side switch comprising the wipers 10], 10-2, .103and 101- is controlled by the private magnet 105 in the usual well-knownmanner. The magnet 106 is the usual release magnet. The line relay 107is connected to the line conductors 80 and 81. The so called back-bridgerelay 108 provides tallc ing battery current for the called substation.The ringing relay 109 is the mean dhrou h which ringing current appliedto tie called line. The busy signaling machine It, as hereinrepresented, comprises an induction coil or transformer, the primarywinding of which is included in a local circuit with a battery and twointerrnpters, one of high frequency and one of low frequency. Throughthe medium of these interrupters an intermittent interrupted current issup plied to the primary winding, which induces an intermittentalternating current in the secondary Winding, whereby when said windingis connected with the subscribers line an intermittent buzzing sound isheard in the receiver.

The substation A and the line switch C are similar in all respects tothe substation A and the line switch C.

A general description of the apparatus having been given, it will now beexplained how a connection is extended from a calling substation A,whose lines terminate in one exchange, to it called. substation A, whoselines terminate in another exchange, the counectien extending through anintermediate exchange. We will assume that the calling subscriber A mustcall the number 22 to ob tain connection with the operator at the ins,tcrnlcdiatc exchange.

Upon the renuhal ot' the receiver from the switch-hook at the substationA preparatory to making a call, an energizing circuit is closed throughthe line winding 14 of the hulividual switch C, thereby attract;- iugthe line armature 1.10. he armature 1.10, upon being attracted, acircuit, through the pulhdmrn coil 12in series with the auxiliarywinding 15. The pull-down coil, u )11 energizing, attracts the plungerarm 10 to force the plunger into the bank of sprin ]7---24, inclusive.it also operates the t-otf armature 16, thereby di onnecting the linewinding l-t from the ine.

The armature 110 does not (all back immediately, hrwverer, owing to thefact that the wil'iding 15 is still in series with the pulldown winding1:2. Upon the plunger? arm in being attracted. the springs 111 and 112are brought. together to short-circuit the auxiliary winding 15, matingthe same slightly w acting. The armature 111') licing set: to fall backallows sutiicient time for a holding circuit to be closed in tie switchahead for the cut-off or holding winding in. The engagement of thesprings 17 and 20 wizl the springs 21 and 24, respectively, extei is thesubscribers lines to the 95 line relay 3b of the selector i The linerelay 30 of the selector switch E is thereupon energized. closing acircuit through the relay 3 The relay 34, upon energizing, closes theahoveanentioned holding circuit through the cut-o'fi winding 13 of theline switch (I. This circuit extends tron: ground. G through the springs113. bank springs 2:3 and 1.8 and the cut-oi? winding 13 to the battery,lead 100, thence through battery B to ground G. The winding 13. uponenergizing, holds the armature 16 and the plunger arm 10 in theiroperated positions after the circuit of the Hill-down winding is brokenby the falling back of the line a rnia'iu re 1'10 A guarditig groundpotential is suppiied to the cornice tor private bank contacts of thecalling line as soon as the relay 34 is energized. This circuit extendsover the circuit 3ust traced to the bank spring 18, thence over thetrim]; 114 to said private bank contact. The eiiergization of the relay34 also prepares euit for the rertical magnet by bringing intoengagement the springs 115 and 116 and opens the circuit of the rel easemagnet at the springs 116 and 117.

The calling subscriber now operates his calling device for the firstdigit 2, whereby the substation impulse springs 7 and 8 are operatedtwice momentarily, each time breaking the circuit of the selector linerelay 30. The relay 34 of the selector being slow acting does notdeenergize during thcmom'entary interruptions of its circuit by the linerelay 30,

.deiinergizes, an impulse is transmitted over the circuit extending fromground G through the contact of springs 119 and 118, springs 121 of therelay 1:32, springs 116 and 1 15 of the relay relay 13 and the verticalmagnet 28 to the battery lead .100. The vertical magnet receives liveimpulses of rurrent over this circuit and operates to raise the switchshaft and wipers two steps to a position opposite the second row orlevel of hank contacts. The oii-noruull springs fl) and 33 close as soonas the shaft is raised one step, but the circuit of the release magnet31 still remains open at the springs 116 and 11.7. The slow acting relayis maintuined in its energized position while impulses are being sentthrough it to the vertical magnet, and in its energized position closesa circuit extending from ground Gr through the springs 123 and 124 andthe relay 126 to the battery lead 100. The relay 1217, upon energizing,closes a locking circuit for itself extending from ground G at the relay1 1 through the springs 113, rotary uuignel springs 129 and 128, normalsprings 33 and the springs 130 and 131 of the relay 1%, thence throughthe said relay 126 to the battery lead 100. Thus, upon thedeenergization oi": the relay 35 after the last impulse delivered to thevertical magnet, the relay 126 remains energized and the circuit of therotary magnet is closed. This circuit cxtendslfrom ground G through.thesprings 113, springs 129 and 128, normal springs 33, springs 130 and131, springs 124 and 1.25, 111-- terrupter springs 127 and the rotarymagnet 29 to the battery lead 100. The rotary magnet, upon energizing,rotates the wipers one step and, by opening the springs 128 and 129,disconnects ground (1 from itself and the relay 12b. If the first trunkline of the second level is idle, the relay 126 decnergizes as soon asthe springs 128 and 129 are opened. If this trunk line. is busy,however, the private wiper 26 finds the contact with which it engagesprovided with a guarding ground potential, which is transmitted to therelay 126 through the springs 130 and 131, thereby preventing itfromdeiinergizing. The rotary magnet, however, denengizes when the springs127 separate, regard.- less of Whether the relay 126 remains energizedor not. If the relay 126 remains energized, the circuit of the rotarymagnet will heagain closed as soon as the armature drops hack far enoughto close the springs 128 and 129. The rotary magnet will thereforeoperate in the manner of a buzzer to advance the wipers step by stepover the contacts until the non-grounded contact of an idle trunk lineis reached by the wiper 26, whereupon the relay 126 dei uergizes. Therelay 1%, upon dei nerg'iziii whether after one or several operations ofthe rotary magi'nct, permanently breaks the circuit of the magnet 29 andcloses the circuit of the switching relay 122. The circuit through Saidrelay 122 extends from ground G through the springs 113.S|)Il11;1s 129and 12S, springs 33, springs 13(1 and 132 and the relay 122 to thebattery lead 100. The relay 122, upon energizing" disconnects the linerelay 3!) from the line and extends the line connection over the heavyconductors through the wipers 25 and 27 to the group of relays M (Fig.2) of the trunk line ill--10. The wipcr25 and 21' making: contact withthe conductors 41 and 4-3, r(2s 'iectii'ely, close a circuit through theline relay 4-7, the said cirruii extending from ground G through thelower winding of the relay 17, Winding 45 of the repeatingcoil S,springs 133 and 131 of the relay 56, the lower winding of said relay.conductor 43, Wiper 27, over the hen vy eonillu-lors, through thesubstation A, over the heavy return conductor, wiper :55, conductor 11.winding 44; of the repeating coil S and the upper winding of the relay4? to the battery B. The relay 47, upon energizing, provides a holdingcircuit for the relay 12 of the selector E and the winding 1b of theline switch 1. The said circuit for the relay 122 of the lertor Eextends from ground G through the contact of springs 13?, conductor "12,Wiper 26, springs 130 and 132 and the relay 122 to the battery lead 100.The holding circuit for the Winding 13 extends over the above-traccdcircuit through the wiper 26,

(iii-normal springs 33, springs 128 and 129, bani? springs 2 and 18 and.through the winding 13 to the battery lead 100. A further result theenergization of the relay 47 is to closean ener izin circuit thron -hthe relays 61 and 62. The said circuit extends from ground G through thesprings 135 and the relays G1 and (12 to the battery B.

The relay 61 energizinp quicker than the relay 62 opens the contacts ofits springs 138 and 131) before the relay G2 closes its contact springs.140 and 141. Therefore the energization of said relays is functionlessat this time. The relay 56, upon energizing, completes a locking circuitfor itself through the springs 136 independent of its energiz ingcircuit. A further result due to the energization of said relay 56 is tomomentarily open the energizing circuit of the relay 4? at the springs13 and 133, and then to again close said circuit at the springs 133 and137, thus connecting the conductor 13 direct to one terminal of theWinding 45 of the repeating coil The said operation of the relay 56transmits one impulse of cur rent through the windings 45 and 44 of therepeating coil S, which impulse of current induces a correspondingimpulse of current in the secondary windings 46 and 47 of said Theinduced impulse exrepeating coil. tends from the point 69 through thewinding 16 of the repeating coil S, trunk conductor 40. Winding 51 of"tho ropunt-ing ruil S, polnrizoil relay -49, winding 50 of tho repeatingroil S. trunk rontluctor 39 and the winding 4? of tho ropuating roil 9hack to the point till. 'lho arniuturo fi-t of tho pulnrizrd rulay 4tresponds to suitl llllPlllHt illltl. rloson u cir- ('llil through therolnys 57 and 38. The billtl oirvuit; tor the relay 57 oxtomls fromground i through tho rontartr of prings 'l 12. springs I44 and ll-i'land tho rt-hiy 57 to tho lmttrry lrzul 200. Thu roluy 57. upon (nor--gi'liing, UltlStS 2i lurking ou-ruit for itself through tho springs H5uiul llil intlupmuh out of its energizing: rirruit. A l'urthor result ofthe rnrrgimlion of snhl rolay is to rlosu n bridge across thet'tilltlHtiOl'H 5!) and 60, thus vnrrgizinyr tlulino rt-lny 1 18 of thosolortor 1*. Thu suiil vnvrgizing rirruit on tennis from ground ti (Fig:t) through tho lowor winding of tho lino roluy 148., springs H9 ulul M9of tho rolay 151. trunl; routluotor till, winding; 523 of tho rupvutin;coil S, springs Ht. springs l t-7. Winding 5; of tho repeating coil 2trunk rmulnrlor it". springs I50 uml la'itl" of tho. ri-luy l-il uiultho upper wintling ol the rvluy t lt; to tho hutlrry lriul 2 'lhrapparatus: is. now in rrzulinrsu for tho opvrution of tho *lih'tl at thoculling Hlllislutiml for the u 1ontl digit J.

The o'|u .r:1tion of tho walling tlt'Yit't. for tho second digit 1 oponstlueurrgizing rirunit, of the relay 1:7 twiro, hut us tho suiil rrluy isslow noting it; (low; not, (luinorgizu during the momentary intnrruptionof its circuit at the substation. lhrrphy prurmuiu tho first selectorl'l tllltl tho lino switch (i from releasing. Thu opuning vand1'lt).'--ill; of tho said iinpulso springs at the sni'istiuion causesthe windings 4t and 15 of tho rcpt-at ing ooil S to inrluoo impulsvn ofrurrmli in the secondary windings t7 mul it'- of mint repoatin coil Thearumturu 54- ol tho )Olfll'lZBt. relay 49 mspoinliug to mill ill- (luccdimpulses oporutos to ropvut the mid. impulses to tho rrlay 5% over u riruil ex tending from ground (2" through tin: routact of springs H23 andthe rvluy on to tlu: buttery lead 200. The rrlny 58 rouponiling to saidimpulses repeats the. sumo to the line relay 148 of the. selector F. Thuoperations of the selector F that; are brought, about by the line relay148 are similar in all. resperts to the operations of the first olootorll. Tho selector F, upon being thus oprrntml. (XllOl'lt'lS the linoconnection to the group of relays K. The roluy 152 of the said group ofrelays thereupon becomes energized and closes n. holding circuit for therelay 1.531 of the selector F and also causes tho linr lump 79 to glow.The holding rircuit For the said relay 151 oxtr-nds from ground G"through tho contact of springs 153 and, 154. wiper 156, contact ofsprings 157 untl 15S and tho relay 151 to tho buttery lead 300.

The operator at the manual board not-i0 lug: tho lamp 7U glowin ginserts the plug {2' ol tho. oortl circuit. 0 into the inch 1 P einsertion of the plug p into the jack j rnusrs thr rrluys 159. 166 and165 to enorgino. Tho energizing circuit for the relay 159 extends fromground G through the contacts of tho nprings 160 and the reluy 159 totho hntxtrry lozul 200. The relay 159, upon rnorgizin opurntou to closea new holding rirrnit for tho ruluy 151 of the selector F and to(liHCflllHNfl l'llu uoinlurtors 161. unit 162 from tlulino roluy 15; umlto connect the Fittitl ('tllllllltiltll'h with tho jnrk spring; 163nlltl Iii-t. rrspm-tivrl The energizing cirt'uil. 'l'or tho roluy ltltttXlt'IltlS l'roni grountl tl through tho .-':|i l rrluy. slrrvo ol" thojack j and tho lHIHll'lHg of tho plug: p to tho lmttory lriul .Ztlt),'lhr rrluy 166, upon out-ruining. t wrutr,-. to rlosr u rirouit' throughtho springs Hi? to inur'r lhr lump 82 to glow. hut the Stiltl rirruit iniunurtliutoly opened at tho spring ms hy tho rnorgizatiou of tho ruinltih. 'l'hp )|)iltlltll' now oporatrs thr lu-y it" to ln-iilgr lu-rtalking not :ioross thilino rotulurlors lil :uul litl guu'l rvrvivrsthe, rolling ulnz-wiln-r! ll'tltl. l pon learning that tho uulN-rilwr:il uhstntion whoso lino ltllllillttltH in u tlistunt oxrhnugo, is\tllllll'tl. sho insrrb tin plu; p into tho jnrk j. \Vo will:lfifilllllt that tho rullwl suhslnlion's number i it). 'lhr inurrtionof the plug 1 into tho jnvk j onuuw thirrluys 171 illltl 172 (Fig. (I)to onvrgzizo on" :1 rirruituxtvruling' from ground ti through tluslttYtol' the pin" p. hushiun' of tin jurh 10G nlul thr rulnyh lit and lit! inStllt'R to thilmttvry ll. 'lhr rni-rgizntiou ol illtl rrluys isllllltlllUllltHH ll this llitlt'. Thu tlllt'l'ill l l\n\\ throws tho korK. hritlfling' lltl milling ll\'i ,'t' 172i tilfl'nSr tho((llltlllt'ltll'i-t 9i unil thus rn rp izing tlw rrluy H 5. 'lho rvlny 523 upon onvrn'ixingr. ttilll'llt'ltS :i lurking cirvnit for itsollthrough tho sprin w li'l pontlrut of its rnorgiviing i-rrni ("on 'aoprrzlt s to transmit. our impulse of current (Wtl' tho fitmtliltlfll'S2, inul 8+ in tho sunw inunnrr as tho rrlay ht: (Fig. 2') operated intho provious instanro. 'llnsaid llllplllSt of rurrent (xii-nth fromground ti" through tlw wintling 17? of tho ropouting coil S over lhruonilurtur 95. through tho ('Ol'tl rirruit. 0. orvr thr returnronilurtor S4 uiul winding 176 of tho rrpouti-ngrroil S" to liuttrry B.This ilnpulw o'l rurrrnt llltlllttS .n rorrvs iontlin gimpulse ofrurront in tho windings 12 'l T :nul 178 of snirl rrpruting roil S, 'lhrllltllltlt'l iinpulsr tXl'tHtlS from tho point 180 through tho winding178 of tho rvprutiug roil P (wonillu'tor R7, winding l' l of thorcprutingrroil S. polarizoil relay i l-1. winding 1 5 182 of thel'QXiltillg (-oil S. ('ontlur-tor S6 and tho winding 17? of thereprinting roil S to tho point 190. 'llum'niuluro 196 of the polurizmlri-ln Vruspmnl; to until impulse ltllll (1030b .1 l through the relays187 and 188. The said circuit for the relay 188 extends from ground (iftthrough the contael of springslot), springsfLtLl and tilt) and the relaylots to battery it. 'lltc"*l'elay 1813,

upon energizing, closes a locl iiug circuit-13nitself through thesprings 'ltlt' and 192 independent of its energizing circuit. A furtherresult of the cnergization of said relay is to close a bridge across theconductors St and so. thus energizing the line relay 107 (Fig. T of theconnector ll. The said oncrgizing circuit extends from ground (1 throughthe lower winding of the line relay 1U? conductor 61. winding 18- of therepeating coil S". springs 193i springs 194, winding 183 of therepeating coil S, conduetor S0 and the upper winding of the line relay107 to the battery lead 300. The said relay. upon energizing, closes an.energizing circuit through the relay 195 from'grouiul i through thecontact of springs 196 and 197 and the relay 195 to the battery lead300. The apparatus is now in readiness for the operation of the dial at;the operator's calling device for the first digit 2.

The operation at the said calling device for the first. digit 2 closesand opens the aforesaid circuit through the windings 175 and 176 of therepeating coil S thus trans mittin two impulses of current through thesaid windings. The said impulses of current induce corresponding im'iulses of current in the windings 178 and 177 of the repeating coil SThe armature 186 of the polarized relay, 185 responding to said 1nducedimpulses operates to repeat the impulses to the relay 187 over a circuitextending from ground G through the contact of springs 189 and the relay187 to battery B. The relay 187 responding to said impulses repeats thesame to the line relay 107 of the connector H. Since the relay 195 isslow acting it does not dei nergize during the 1nomentary interruptionsof its circuit by the relay' 107, so that each time the latter relay isdeiinergized a circuit. iscloscd exteinling from ground G through thecontact of springs 196 and 198, springs 201 and 199, relay 202. verticalmagnet 97 and the side switch wiper .101 (in first-position) to thebattery lead 300-. The vertical magnet 97 receives two impulses overthis circuit and operates to raise the switch wipers 94. 95 and 96 to aposition opposite the second level of bank contacts. The relay 202.which was included in Series with the \vertical magnet. remains in itsenergized position during the. entire time that impulses are being sentthrough it and operates to close the circuit of the private.magnet 105.After the last impulse is delivered. the relay 202 opens the. i

circuit of the private magnet 105, which. upon deenergiaing, permits theside switch to advance from first to second position. The movement ofthe side switch wiper 101 tors shown to'the called substation.

from first to second position transfers the battery connection from thevertical magnet, J7 to the rotary magnet 98. The operator now operatesher calling device for the last digit 0. in response to which theconnector line relay operates to transmit ten impulses through therotary magnet 98 in series with the relay 202. whereby the shaft Wipersare rotated onto the contacts of the desired line. H the called line isidle. the private magnet 10;) dei nergizes when its circuit is broken bythe relay 202 after the last impulse is deliverod. to the rotary magnet.The denergization of the said private magnet 105 allows the side switchto advance one more positionthat is, from second to third position. Bythe engagement of the wipers It)? and 104 with their third-positioncontact points and by the energization of the ln'idge-cut-otl winding203 of the line switch (T. the eonnection is completed over the heavy('oinlll(.-- The circuit for. the bridge-cut-ofi' windin'g 203 of theline switch C extends from ground (1 through the side switch wiper 102(in third position), private wiper 95, conductor 204 and the winding203to the battery lead 30 A guiu'ding ground potential is supplied tothe connector private bank contactof the called line, which prevents thecalled line from being seizedby some other connector switch. By theengagement of the side switch wiper 191 with its third-position contaetpoint. the circuit of the ringing relay 109 is closed. This circuitextends from ground G through the interrupter 205i relav 1H9, springs206 and the side switch wiper 101 (in third position) to the batterylead 300. Theringing relay; upon energizing. disconnects the callingline from the called line and bridges the ringing current generator hacross the called line to signal the called subscriber. The ringingrelay 109 is energized only intermittently through the medium of theinterrupter 5205. Upon the response of the called subscriber his line isprovided with talking current; through the windings of the larch-bridgerelay 108,Wh.ich

'rclay upon energizing. closes the circuit of the ringing eat-off relay207. The said circuit extends from ground G through the side switchwiper 102 (in .third position), springs 208 of the relay 108 and theringer cut-off relay 207 to the battery lead 300. The relay 20? uponenergizing, interrupts the circuit of the ringing relay 109 at thesprings 206 and closes a locking circuit for itself through its on nsprings 209 independent of the springs 208 of the back-bridge relay N18.The operator 110W restores'the key It to normal, thus connecting thecalling and called substations over the heavy conductors shown.

After the conversation is conuiileted, the connection is released uy thehanging up of the receiver at the calling substation in the followingmanner: When the receiver at the substation A is restored to theswitchhoolc, the separation of the luck-switch spring destroys theenergizing circuit of the relay 17 of the group of relays M. The

r lay 47, upon dciinergizmg, opens the hold mg circuits for the relay122 of the selector E, the holding winding 0 and the relays 61 and 62 ofthe group of relays M. The deiinergization of the relay 1.22 of theselector E closes the circuit of the release magnet 31 of said selector.The said circuit extends from ground G through lhc contact of springs119 and 118, springs 121, springs 116 and 117, ofl-noriml springs 32 andthe release magnet 31 to the battery lead 100. The magnet 31, upondeenergizing, restores the switch shaft to normal position and its owncircuit is broken at the oft-normal. springs 32 when the shaft reachesits lowest position. The winding 13 of the line switch (1. upon becomingdeiinergized, allows the plunger arm 10 to return to normal position.The relay 61 dei nr-rgizing quicker than the relay 62 operates t transmit an impulse of current through l' -e Wifltlings 45 and 44- of therepeating coil 55. The said impulse of current extends from the positivepole of the high voltage battery B through. the contact of springs 110,springs 139. winding 45 of the repeating coil S, lower winding of therelay 47. the positive pole of battery B, through battery B, h perWinding of the relay l7, Winding 41 o the repeating coil fisprings 138and the springs 141 to the opposite pole of battery 15. As shown in thedrawings the relay ll-is a p larized relay, and although current at thistime passes through the winding of said. relay its armature will not beattracted as the current in the above traced circuit from the hi ghvoltage battery B is flowing in the opposite direction from that whichis re quired for the o era tion of this relay. The said impulse o'lcurrent induces a corresponding impulse of current in the windings 46and 47 of the repeatin Y coil S extending from the point 68 throng 1 thewinding 47 of the repeating coil S, conductor 39, Winding 50 of therepeating coil S liola-riaerlv relay 49, winding 51 of the repeatingcoil S, conductor 4.0 and the winding 46 of the repeating coil to thepoint 68. The armature 55 of the polarized relay responding to saidimpulse opens the holding circuit of the relay 57 at the springs 216.The relay 57, upon delinerg'izing, opens the bridge across theconductors 59 and 60. thus allowing the line relay 165 of the cordcircuit 0 to dciinergize. The relay 165, upon deem ergizing, closes acircuit through the supervisory lamp 82, thus signaling the operatorthat the connection has been terminated. The operator removing the plugp from 13 of the line switch 1hr jack j destroys the energizing circuitof the relays 166 and 159. The relay 159, upon det'cncrgizing. opens theholding circuit of the relay 151 of the selector F at the springs 211,which allows the selector to return to normal position in a mannersimilar to that hcrcinbefore described for the selector E. The relay166, upon dei nergizing, opens the circuit of the supervisory lamp 82 atthe springs 167. The operator then removes the plug from the jack j,which destroys the holding circuit of the relays 171 and 172 of thegroup of relays Q, (Fig. 5). The said relays, upon dciinergizing, causethe relay 188 (Fig. 6) to open the energizing circuit of the line relay107 of the connector H in the same manner that -the relay 57 (Fig. 3)opened the energizing circuit of the relay 165 of the cord circuit 0.

the circuit ol the relay 195, thus completin a circuit extending fromground G t n'oug the contact of springs 196 and 198, springs 201 and212, off-normal springs .213 and [he release magnet 106 to the batterylead 300. The inagl'uel, upon energizing, restores the switch shaft andside switch wipers to normal position and its own circuit is broken atthe springs 213 when the shaft reaches its lowest position.

It the number called is busy, there will he a guarding p tential uponthe connector private bank contact, just as explained in connection withthe line switch C. The connector private wiper 95. upon engaging thisguarding contact, and before the side switch wipers have passed to thirdposition. coinpletcs an energizing circuit through the busy relay 5314.This circuit extends from ground at the private wiper through the sidesvitrh wiper 102 (in second position), springs 217 and JUL relay 214-.springs 220 and 2151 and the priva c magnet 165 to the battery lead 2W0.The privale nuignct is thus hold encrgizwl and retains the side switchin second position. The relay :14. upon energizing. opens the circuit oflhe rotary magnet 98 at the springs 215. and also circuit for itselfbringing th spring .218 into contact with the spring 316, therebydisconnecting the spring 2 16 from the spring 217. The en gagenient ofthe springs a-circuit for the busy tone extending from the busy machineL through the said springs 2'19, side switch Wiper 104 (in secondposition), condenser 292. over the heavy conductor. through the callingtelephone and over the return conductor to the busy machine l). Thecalling subscriber. upon receiving the busy signal, replaces hisreceiver upon the receiver hook, thereby releasing the connection in themanner above described.

it having been explained how a connection is completed from thesubscriber A to The relay 107. u ion deiinergizin 0 mos 21,9 serves inclose I the subscriber A by moans of physical circuit trunk linos. itwill now bo explained how the anbncribor may call the suhscribor A ovcrphantom oirouit trunk lines. We will assume that tho milling subscribermust; call the number 32 to obtain connection with the oporatru' at thoinlorniodiato exchango ()\(l' a phantom circuit. trunk lino. Sineo theopt-rations of tho lino switch U and tho acleotor ll havo heroiuliotoroboon dosouboil. no will assumo that tho auhaorihor A has romovorl hisroooiror and rotated his dial for tho liral digit 3 Hninorliug tho.wipols 1Z5, Qfifillltl :3? of tho iii-at Hiltt'lUI' E with tho hankmutants 22th .2124- aud As soon as tho oounortir'in is romplctorl to theconductors 2'16, 22? and 228. tho lino relay 7-1 oil. the rupoater I(Fig. 4) is energized, said oirouit oxtonding from gromul ti through tholowor winding of tho rolay 7r conduntor 228, through tho nubstation A,over the return conductor 2% and through tho nppor winding ol' the rolayH to the huh tory lead 100, lh rolay Tl. upon (um-giviin;g olosos arirruit through tho rolajr 7:") and hrulggos tho hnpodanro coil 223:u'roas tho trunk conihiolori: tit -l0 and 3 til. 'llio ouorgrizingrirouii for tho rolay 7h ox tonds from ground (i through the ront'aot ofsprings 230 and 2'29 and tho relay T5 to tho battery load 100. The rolay75. upon onorgizing. oomplotoa holding oircuit for the rola 12" of thoz-+oloolor E and the hold in;: winding 13 of tho lino switch ("1 Thesaid holding: (ll'titlt for tho rola} l2) oxttlltlH From ground (1through tho mutant, of springs 23), oorulnolor 252T. uipor L 6 springs13'") and 132 and tho rolay ['32 to tho hattory load lll l Tho holdingrirruilfor tho uiniling Ill ol th" lino swiu-h oxtonlls oror thoalmrolraood c irruit to tho o. ipor 26 Mom hor iho ('iHlill oxtoudnthrough tho ooulaot ot' sprin -w 21i; -pring lliw and lf'iih hank apringand. W and through tho winding t2) to tho lmllorr load l ll'i. 'lliolol'lniual ((illlllll'llil'h 1'; and Q7 of tho phaw tom rircuit trunkmay torminato in a solw tor switvh in tho intornwdiato ouchaugo (notshown) aimilar to tho s lot'tor F.

\Vhon tho calling; dc\ h'o at tho aul-ataiion" is oporatoil. thowaparalion of tho ilupnlxo springs 7 and H allows lho lino rolar Tl o'ltho ropoator l to doonorgixo. llarh limo tho rolar Tl iloi uorn'izos.tho wpriuoj 121m nuuuru larily disonggagm tho spring! 22 and ongmgoa thospring 2 3i and tho aprin g 2 1 dison gag-m tho RPllltLl' 217-5. Theoporati n f tho Hprinoa .lf l and 235 opons tho hridoo arrow thoondin-tom tit" and 63. than roru-atiu; tho ihipnlaos from thoauhstatimi to tho so lortor switch at. tho intormodiato oxohange. Sinootho rolay 7.) is slow noting it does not, loi norn-irw during thomomontary soparation of tho springs: .229 and 230. (onscqucntly thecngagen'iontof tho springs .230

and 231 (loses a rircuit. through the relay Tt. This circuit oxtoudsfrom ground G through the rontart of springs 230 and 231, springs 236and tho rolay 76 to the battery lead 100. "lho rolay 76 is energizedbytlie first, impulst and, being slow acting, remains in its operatedposition until all'the impulses for the digit. are. delivorod. In it'tsonorgizoll position the relay 76 operates to dmconnort tho oonduotors64* and 65 from tho roiuilonsors 'TT and 78 and to ahnrt-cirouit; theimpodanoc coil. 233 to prevent its iutcrt'oronoo with tho operation ofthe switches at tllo distant exchange.

Whon the substation calling dorice is operated for the second digit 2,tho ropoator oporatcs in the manner oxplainod to repeat two irnpulhosovor tho trunlc conductors- 39---4O and (5341l to a selector in theintornu-diato uxchango. This Helootoi' oporatos in tho same uiannor astho solootor F to' oxtond tho connection to a group of relays similar totho group of relays K. Tho opt'rtor amwors by moans of at 00rd oircuit 0similar to tho cord circuit 0, ox'copt that tho proliinluary llllPlllSProlay 835 is tlispclhml with. 'Ihc oporator, upon rocoiviug the railing:snhscribofs ordor, insor-tS tho plug p into a jack ronnootcd to thephantom tap conductors and 91 of tho trunk lines 86--8T and Si --89,which extends the connection to the third oxchaugo. The plan tom tapConductorn 9:? and 93 (Fig. (3) or the mid trunk linos 8(3S7 and SH-- Sltorniinato in a counoctor Hwitoh (not shown) in the third oxrhang'osimilar in all rcsports' to tho connootor switch ll. Tho operator thouliridg'os hor (-allintr \lovioo (tho impulse nprings lloinu' normallyrlowil) across tho phantom tap conductors 9() and 1 and opou atos thodial in :n-rordanoo with tho dosirod numbor to comploto the uonnootionto tho oallod suhsrribcr, as horoinho'l'oro dost'rihodi 'lho roloa o oftho apparatus is priu'tioally tho mun as ln-roinlwl'oro iuonlionoil andis llilllilll'tl h tho walling uuhaoribor X roplarin hi rovoivor upontho toroiror hook.

It will thus ho soon that, I havo devised a 'ory ollirirnl form ofautomatio tolcphonc s wtom in which a phantom circuit can he aiwri|npimod on trunk linon over which an aulou|atironuooti'on isvatahlishod. this beng brought about in such a mannor that noithor ouoot' tlioso rounootions intorforos in "any way with tho othor.Flutluumorr.

it will ho soon. that tho oonuootiou can ho ,of 'said subscribers lines,and a phantom signaling circuit superimposed on said trunk lines.

2. In a telephone system, ,a plurality of subscribers lines, meansincluding a trunk line and automatic switches controlled over said trunkline for extending a connection between two of said lines, a secondtrunk line and automatic switches controlled thereover for establishinga second connection between two of said lines, and a phantom signalingcircuit superimposed on said trunk lines.

3. In a telephone system, a plurality of subscribers lines, meansincluding a trunk line and automatic switches for extending a connectionbetween two of said lines, means including a second trunk line forextending a second connection between two of said subscribers lines, aphantom circuit superimposed on said trunk lines, and means includinautomatic switches for establishing a ta king circuit including saidphantom circuit.

4. In a telephone system,a plurality of subscribers lines, meansincluding a trunk line and automatic switches controlled over said trunkline for extending a connection between two of said lines, a secondtrunk line and automatic switches controlled thereover for establishinga second connection between two of said lines, a phantom circuitsuperimposed on said trunk lines, and means includin automatic switchesfor establishing a ta king circuit including said circuits, and aphantom signaling circuit superimposed on said physical circuits.

6. In a telephone system, a pair of physical'trunk circuits, means forcontrolling antomatic switches over either of said physical circuits,and a phantom signaling circuit superimposed on a portion of saidphysical circuits, said portion of the physical circuits beingconductively insulated from the remainmg portion of said circuits.

7. In a telephone system, a pair of physical trunk circuits, means forcontrolling antomatic switches over either of said physical circuits, aphantom circuit superimposed onsaid physical circuits, and means forcontrolling automatic switches over said phantom circuit to establish atalking circuit.

8. In a telephone system, a pair of physical trunk circuits, means forcontrolling automatic switches over cithc'r of said physical circuits, aphantom circuit superimposed terminating in the primary winding of an.

induction coil, a second trunk terminating in the secondary of saidinduction coil, a re lay at the opposite end of said second trunk, andmeans for automatically transmitting an impulse through the primary ofsaid induction coil when connection is made with said first trunk tothereby induce an impulse of current by clectrrmiagnetic inducl ion insaid second trunk to thereby operate said relay.

11. In a telephoncsystcm. a trunk line terminating in the primarywinding of an induction coil, a second trunk terminating in thesecondary of said induction coil, a relay at the opposite end of saidsecond trunk, means for automatically transmitting an impulse though theprimary of said induction coil when connection is made with said firsttrunk to thereby induce an impulse of current in said second trunk tothereby opcrate said rclay, a third normally inoperative trunkinductively associated with said second trunk, and meanscontrolled bythe initial operation of said relay for renderin said third trunkoperative.

I2. In a telephone system, a trunk line, a relay in said trunk, meansimluetivoly rclatcd to said trunk for trmismitting a series of inducedimpulses over said trunk to operate said relay, and 'an automatic switchcontrolled by said relay.

13. In a telephone system, a plurality of subscribers lines, mcaus'forestablishing a connection between two of said lines. said meansincluding a trunk line ronduciively insulated from the remainder of saidcon nection, and automatic switches for use in establishing saidconnection controlled by induced impulses transmitted over said conductively insulated portion of said lrunk line by electromagneticinduction.

14- In a telephone system, a plurality of subscriberslines, a trunkline, a second trunk inductively related to said first trunk, a relay insaid second trunk, means for extending a connection from a calling lineto said first trunk, means for transmit in? a, p urality of series ofimpulses to said rst ffinlg; means for thereby inducing a correspondingseries of impulses in said second trunk and through said relay byelectromagnetic induction, and means including an automatic switchcontrolled by said relay for completin the connection to it called line.

15. n a telephone system, a polarized relay, an automatic switch, andmeans for operating said relay by induced impulses of one direction tooperate said switch and by induced impulses of the opposite direction tocontrol the release of said switch.

16. In a telephone system, a trunk line, a polarized relay n said trunk,means lnducs li\ely related o said trunk to transmit a series of inducedimpulses over said trunk in one dirc tion to operate said relay, an an tmati switch controlled by said operation f said relay, means fortransmitting an induced impulse over said trunk in the oppo sitedirection to again operate said relay, and means controlled by thelatter operation of said relay to release said automatic switch.

17. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between two of said lines, said meansincluding a trunk line conductively insulated from the remainder ofsaid. conmotion, and automatic switches for use in establishing saidconnection controlled by induced impulses transmitted in one direc tionover said conductively insulated portion of said trunk line. andreleased by an induced impulse transmitted in the opposite directionover said portion of said trunk line.

18. In a telephone syslem, a plurality of subscribers lines, a trunkline. a second trunk inductively related to said first trunk, apolarized relay in said second trunk, means for extending a connectionfrom a falling line. to said lirsl trunk, means for transn'iitting aplurality of series of impulses in one diil'ection over said firsttrunk, means For therdliy inducing the corrcspondiin, rics of impulsesin said second trunk through said relay, an automatic switch controlledby said operation of said relay, means for transmitting an inductiveimpuls" if the opposite direction through said relay, means controlledby this last operation of the relay .to control the release of saidswitch, and means controlled by said switch for completing theconnection to a aillcd line.

19. In a telephone system, trunk line, a normally inoperative trunkextending therefrom, meanstl'or establishing connection with said firsttrunk, means controlled by the establ'islnncnt of said connection forrendering said second trunk operative, a third trunk line, and a phantomsignaling circuit superimposed on said first and third trunk lines.

20. In a telephone system, a trunk line, a imrtnally inoperative trunkextending therefrom, means for establishing connection with said firsttrunk, n'icans controlled by the establishment of said connection fortransn'iitting a preliminary impulse over.

said first trunk to render said second trunk operative, a third trunkline, and a phantom signaling circuit superimposed on said first andthird trunk lines.

21. In a telephone system, a trunk line, a second normally open trunkinductively associated with said first trunk, means for establishing a.connection with said first trunk, means controlled by the establishmentof said connection for closing said second trunk, a third trunk line,and a phantom signailing, ircuit. superimposed on said lirst and thirdtrunk lines.

2. in a telephone system, a trunk line terminating in the primarywinding. of an induction coil, a second trunk terminating in thesecondary of said induction coil, a relay at the opposite end of saidsecond trunk, means for autolnatically transmitting an impulse throughthe primary of said induction coil when connection is made with saidfirst trunk to thereby induce an impulse of current in said second trunkto thereby ope ate said relay, a third trunk line, and a phantomsignaling circuit supcrinniosed on said sec ond and third trunk lines.

255. In a telephone system, a trunk line terminating in the primarywinding" of an induction coil, :1 second trunk terminating in thesecondary of said induction coil, a relay at the opposite end of saidsecond trunk, tin-ans for automatically transmitting an impulse throughthe primary of said induction coil when connection is made with saidlirst. trunk to thereby induce an impulse of current in said secondtrunk to thereby operate said relay, a third normally inoperativetrunk'inductively associated with said second trunk. means controlled bythe initial operation of said relay for rendering said third trunkoperative, a fourth trunk line, and a phantom signaling circuitsuperimposed on said second and fourth trunk lilies.

24. In a telephone system. a trunk line, a relay in said trunk,meansinductively rclatcd tosuid trunk for transmitting a series ofinduced impulses over said trunk to operate said relay, an automaticswitch controlled by said relay, a second trunk line, and a phantomsignaling circuit superimposed on said trunk lines.

25. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between two of said lines, said meansincluding a trunk line conductively insulated from the remainder of saidconnection, automatic switches for use in establishing said connectioncontrolled by induced impulses transmitted over said conductivelyinsulated portion of said trunk line, a second trunk line, and a phantomsigi aling circuit superimposed on said trunk mes.

26. In a telephone system, a plurality of subscribers lines, a trunkline, a second trunk inductively related to said first trunk, a relay insaid second trunk, means for extending a connection from a calling lineto said first trunk, means for transmittin a plurality of series ofimpulses to said rst trunk, means for thereby inducing a correspondingseries of impulses in said second trunk and through said relay, means includin an automatic switch controlled by said re ay forcompletin theconnection to a called line, a third trun line, and a pliantom signalingcircuit superimposed on said second and third trunk lines.

27. In a telephone system, a trunk line, a polarized relay in saidtrunk, means inductively related to said trunk to transmit a series ofinduced impulses over said trunk in one direction to operate said relay,an automatic switch controlled by said operation of said relay, meansfor transmitting an induced impulse over said trunk in the oppositedirection to again operate said relay, means controlled by the latteroperation of said relay to release said automatic switch, a second trunkline, and a phantom signaling circui-t superimposed on said trunk line.

28. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between two of said lines, said meansincluding a trunk line conductively insulated from the remainder of saidconnection, automatic switches for use in as tablishing said connectioncontrolled by induced impulses transmitted in one direction over saidconductively insulated portion of said trunk line and released by aninduced impulse transmitted in the opposite direction over said portionof said trunk line, a second trunk line, and a phantom signaling circuitsuperimposed on said trunk lines.

29. In a telephone system, a plurality of subscriberslines, a trunkline, a second trunk inductively related to said first trunk, apolarized relay in said second trunk, means for extending a connectionfrom a calling line to said first trunlqmeans for transmitting aplurality of series of impulses in one direction over said first trunk,means for thereby inducing the corresponding. series of impulses in saidsecond trunk 'through said relay, an automatic switch controlled by saidoperation of said relay, means for transmitting an inductive impulse ofthe opposite direction through said relay, means controlled by this lastoperation of the relay to control the release of said switch, meanscontrolled by said switch for completing the connection to it calledline, a third trunk line, and a phantom signaling circuit superimposedon said first and third trunk lines.

30. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between a pair of said lines, means forestablishing a second connection between another pair of said lines,both of said means including a trunk line, together with a normallyinoperative trunk extending therefrom, means for establishing connectionwith either of said first trunks, means controlled by the establishmentof said connections for rcndering the corresplonding second trunkoperative, and a p antom signaling circuit superimposed on said firsttrunks.

31. In a telephone system, a plurality of subscribers lines, means forestablishing connection between a pair of said lines, means forestablishing a second connection between another pair of said lines,both of said means including a trunk line, together with a normallyinoperative trunk extending therefrom, means for establishing connectionwith either of said first trunks, means controlled by the establishmentof said connections for transmitting a. preliminary impulse over thecorresponding first trunk to render the corresponding second trunkoperative, and a phantom signaling circuit superimposed on said firsttrunks.

32. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between a pair of said lines, means forestablishing a second connection between another pair of said lines,both of said means including a trunk line, a second normally open trunkinductively associated with each of said first trunks, means forestablishing a connection with either of said first trunks, meanscontrolled by the establishment of said connections for closing thecorresponding second trunk, and a phantom signaling circuit superimposedon said first trunks.

33. In a telephone system, a pair of trunk lines, a relay in each ofsaid trunks, means inductively related to each of said trunks fortransmitting a series of induced imfor establishing a second connectionbetween two other of said lines, each of said means including a trunkline conductively insuluted from the rcn'iainder of the correspondingconnection, automatic switches for use in establishing said connectionscontrolled by induced impulses transmitted at the conductively insulatedportion of the corresponding trunk line, and a phantom signaling circuitsuperimposed on the conductively insulated portions of said two trunks.

35. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between two of said lines, means forestablishing a second connection between two other of said lines, eachof said means including a trunk line conductively insulated from theremainder of the corresponding connection, automatic switches for use inestablishing said connections controlled by induced impulses transmittedat the conductively insulated portion of the corresponding trunk line,a. phantom signaling circuit superimposed on the comluctively insulatedportions of, said two trunks, and means for controlling automaticswitches to establish a third talking circuit over said phantom circuit.

343. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between two of said lines, means forestablishing a second connection between two other of said lines, eachof said means including a trunk line comluctivcly insulated from therenniinder ot' the corresponding connection, automatic switches for usein establishing said connections operated by induced impulsestransmitted in one direction over said conductivcly insulated portion ofthe correspomling trunk line and released by induced impulsestransmitted in the opposite direction, and a phantom signaling circuitsuperimposed on said conductircly insulated portions of said two trunks.

iii. In a telephone system, a plurality of subscribers lines, means forestablishing a connection between two of said lines, mean forestablishing a secondconnection between two other of said lines, each ofsaid means including a trunk line conductively insulated from theremainder of the correspond ing connection, automatic switches for usein establishing said connections operated by induced impulsestransmitted in one direction over said eondllrtivcly insulated portionof the mirrespomlingtrunk line and released by inducedimpulscstransmitted in the op posite dircct ion, a phantom signalingcircuit. superimposed on said conductivcly insulated portions ol saidtwo trunks, and means for controlling automatic switches to establish athird talking), circuit over said phantom circuit.

3H. lo a telephone system. a trunk line, means l'or cxlending aconnection to said trunk, a generator at one end of said trunk, apolarized relay at the opposite end of said trun k, a normally opencircuit for extending a connection from said trunk, means for musing thegenerator to produce a preliminary impulse to operate said polarizedrelay to close said normally open trunk when connection is establishedwith said first trunk, means for subsequently controlling the generatorto send a series of. impulses through said relay, and an automaticswitch connected to the opposite end of said second trunk controlled bysaid relay.

3!). In a telephone system, a calling and it called subscribens line.means for extending a connection between said lines, said meansincluding a physical phantom circuit, automatic switches for extending aconnection from a calling, line to said circuit, an open ators board,means for extending a connee tion from said physical phantom circuit tosaid opcrators board, a second physical phantom circuit, means forextending a connection from said operatoNs board to said second physicalphantom circuit, and automatic switches for extending a connection fromsaid second physical phantom circuit to the called line.

4H. In a telephone system, a section of a talking circuit, a bridgeacross said section, a second talking circuit passing through a point insaid bridge. a second bridge acro s said section, said second talkingcircuit passing also through a point in said second bridge, and anautomatic progressively mo able switch associated with said secondbridge and controllable thereby.

41. In a telephone system, a section of a talking circuit, a bridgeacross said section, a second talking, circuit passing through a point.in said bridge, a second bridge across said section, said second talkingcircuit pass-- ing also through a point in said second bridge, aninductive windingin said first bridge, a relay in said second bridge,and an automatic switch controllable through the medium of said relay.

4-2. In a telephone system, a section of a talking circuit, a bridgeacross said section, a second talking circuit passing through a point insaid bridge, a second. bridge across said section, said second talkingcircuit passing also through a point, in said second bridge. aninductive winding in said first. bridge. a relay in said se ond bridge,and an automatic progressively movable switch associated with saidsecond bridge and controllable thereby.

l3. lo a telephone system, a section of a talking circuit, a bridgeacross said section, a second talking circuit passing through a point insaid bridge, a second bridge across said section, said second talkingcircuit pass ing also through a point in said second bridge, aninductive winding in said first bridge, a relay in said second bridge,and an automatic progressively movable switch associated with saidsecond bridge and controllnble through the medium ot said relay.

44. In a telephone system, a pair of con ductors for talking purposes, apair of bridges across said conr uctors, a second talking circuitpassing through a point in each of said bridges, and an automatic switchassociated with one of said bridges and controllable thereby.

45. In a telephone system, a pair of conductors for talking purposes, apair of bridges across said conductors, a second talking circuit passingthrough a point in each of said bridges, an inductive winding in one ofsaid bridges and a relay in the other, and an automatic switchcontrollable through the medium of said relay.

46. In a telephone system, a pair of condoctors for talking purposes, apair of bridges across said conductors, a second talking circuit passingthrough a point in each of said bridges, an inductive winding in one ofsaid bridges and a relay in the other, a line, means for extending thetwo sides of said line into inductive relation with said Winding, andmeans controlled over said line for inducing current in said winding tooperate said relay.

47. In a telephone system, a pair of conductors for talking purposes, apair of bridges across said conductors, -a second talking circuitpassing through a point in each of said bridges, an inductive winding inone of said bridges and a relay in. the other, a line, means forextending the two sides of said line into inductive relation with saidwinding, means controlled over said line for inducting current in saidwinding to operate said relay, and an automatic switch controllablethrough the medium of said relay.

48. In a telephone system, a pair of condudtors for talking purposes, apair of bridges across said conductors, a second talking circuit passingthrough apoint in each of, said bridges, an inductive Winding in one ofsaid bridges and a relay in the other, a line, means for extending thetwo sides of said line into inductive relation with said winding, meanscontrolled over said line for inducing current in said winding tooperate said relay, other lines, and an automatic switch controllablethrough the medium of said relay to extend connection to one of saidother lines.

49. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a pair of bridges for each of said sections, athird talking circuit passing through a point in each of said bridges,an automatic switch associated with a bridge at each of said sectionsand controllable tgereby, i, a 1

including a relay,

50. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a pair of bridges for each of said sections,one bridge in each of said pairs including a relay, a third talkingcircuit passing through a point in each of said bridges, and anautomatic switch controlled by each of said relays.

51. In a telephone system, a section-of a talking circuit, a section ofa second talking circuit, a pair of bridges for each of said sections,one bridge in each of said pairs including a relay, the other bridge ineach of said pairs comprising an inductive winding, a third talkingcircuit assing through a point in each of said bri ges, and an automaticswitch controlled by each of said relays.

52. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a pair of bridges for each of said sections,one bridge in each of said pairs including a relay, the other bridge ineach of said pairs comprising an inductive winding, a third talkingcircuit passing through a point in each of said bridges, an automaticswitch controlled by each of said relays, and means for inducingcurrents in one of said, windings to operate the associated relay forcontrolling its associated automatic switch.

53. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a pair of bridges for each of said sectiom, athird talking circuit passing through a point in each of said bridges,an automatic switch associated with a bridge at each of said sectionsand controllable thereby, other automatic switches, and means forcontrolling one or more of said other switches over said third talkingcircult.

54. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a pair of bridges foreach of said sections,one bridge in each of said pairs including a rela a third talkingcircuit passing through a point in each of said bridges, an automaticswitch controlled by each of said relays, other automatic switches, andmeans for controlling one or more of sald other sw itches over saidthird talking circuit.

55. In a telephone system, a section ,of a talking circuit, a section ofa second talkin circuit, a pair of bridges for each of sai sections, onebridge in eachof "said,pairs the other, bridge in each of said pairscomprising an inductive winding, a t ird talking circuit passing througha point in each of said bridges, an automatic switch controlled by eachof said relays, other automatic swltehes, and means for controlling oneor more of saidpther switches over said third talking circuit.

56. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a pair of bridges for each ol said sections,one bridge in each of said pairs including a relay, the other bridge ineach of said pairs con'iprising an inductive winding, a third talkingcircuit passing through a point in each of said l'n'idgcs, an antoniatieswitch controlled by each oi said relays, means for inducing currents inone of said windings to operate the associated relay for controlling itsassociated automatic. switch, other auton'iatie switches, and means forcontrolling one or more of said other switches over said third talkingcircuit.

57. In a telephone system, a pair of conductors for talking purposes, asecond pair of conductors for talking purposes, a pair of bridges foreach of said conductor pairs, a circuit passing through a point in eachof said bridges and an automatic switch controllable over said circuit.

58. In a telephone system, a pair of conductors for talking purposes, aSecond pair of conductors for talking purposes, a pair of bridges foreach of said conductor pairs. a circuit passing through a point in eachof said bridges, a snbscriher s line, no antomat ie switch, means forextending said line by way of said circuit into connection with saidswitch, another subscribers line accessible to said switch, and meansfor controlling said switch. over said circuit to connect the. twosubscribers lilies.

59. In a telephone system, a pair of conductors for talking purposes, asecond pair of conductors for talking purposes, a pair of bridges foreach of said coinluctorpairs, automatic progressively movable means forestablishing a pair of talking connections each of which connectionsincludes one of said conductor pairs, a circuit mssing through a pointin each o'l said bridges, and an automatic switch controllable over saidcircuit.

60. In a telephone system, a section of a talking circuit, a windingincluded in said section, a second talking circuit including saidwinding, a relay in said section. said second talking circuit includingalso the coils of said relay, and an automatic switch controlled by saidrelay.

($1. In a telephone system, a section of a talking circuit, a windingincluded in said section, a second talking circuit including saidwinding, a relay in said section, said second talking circuit includingalso the coils of said relay, an automatic switch controlled by saidrelay, and means for. inducing current impulses in said winding tooperate said relay.

62. In a telephone system, a section of a talking circuit, a windingincluded in said section, a second talking circuit llit'llltlillfl,said. winding, a relay in said section, said second talking circuitincluding also the coils of said relay, an automatic switch controlledby said relay, a plurality of extensions for said section associatedwith said switch, and means for inducing current impulses in saidwinding to operate said relay, whereby said switch is controlled inextend the said section via one of said extensions.

ea. In a telephone system, a section of a talking circuit, a windingincluded in said section, a scconl talking circuit including saidwinding, a relay in said section, said second talking circuit includingalso the coils of said relay, an automatic switch controlled by saidrelay, a plurality of exten sions for said section associated with saidswitch, means for inducing current impulses in said winding to operatesaid relay, whereby said switch is controlled to extend the said sectionvia one of said extensions, and means for inducing a different currentinipulse in said winding to operate said relay in a dill'crent manner torelease said switch.

ti l. In a telephone sy tem, a section of a talking circuit. a sectionof a second talking circuit, a winding and a relay in each of saidsections, a third ircuit including all of said windings and all of saidrelays, and an auto nialic swilch associated with each of said relaysand controllable thereby.

(35. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a winding and a relay in each of saidsections, a third circuit including all of said windings and all of saidrelays. and an automatic switch. controlled over said third circuit.

86. In a telephone system, a. section of a talking circuit, a section ofa second talking circuit, a winding and a relay in each of saidsections, a third circuit including all of said windings and all of saidrelays, an automatic switch associated with each of said relays andcontrollable thereby, and an automatic switch controlled over said thirdcircuit.

(37. In a telephone system, a section of a talking circuit, a section ofa second talking circuit, a winding and a relay in each of saidsections. a third circuit including all of said windings and all of saidrelays, an automatic switch associated with. each of said relays andcontrollable thereby, another .section for each of said first and second talking circuits inductively related to the windings therein, andmeans for of feeling current changes in one of said last sectionswhereby one of said relays is open ated by currents induced in itsassociated winding.

68. In a telephone system, a section of a talking circuit, a section. ofa second talking circuit, a winding and a relay in each of saidsections, a third circuit including all of said windings and all of saidrelays, an

